IR thermometers are fast becoming a staple item in health care operations and have revolutionized routine care procedures by eliminating or dramatically reducing the lag time associated with temperature determination in diagnosis. As opposed to prior temperature measuring devices such as conventional mercury thermometers, an IR thermometer is a sophisticated optical--electronic assembly with precision designed and assembled components requiring tightly toleranced and exacting specifications for proper operation. Attention is directed to the teachings of U.S. Pat. No. 4,797,840 entitled "Infrared Electronic Thermometer And Method For Measuring Temperature" by Jacob Fraden, for a general description of IR thermometer design and operative characteristics. The teaching of the above-identified patent is incorporated by reference.
A critical aspect of IR thermometer operation is the positional arrangement of the wave guide and the sensor inside the body of the device. From a functional standpoint, the wave guide acts to collect the radiation emanating from the tympanic membrane of the patient's ear and accurately guide this radiation to the sensor with minimal external influences. The sensor receives the guided radiation and generates a temperature reading as characterized by the quantum of radiation sensed. The accuracy of the resulting reading depends in part on the purity of the IR radiation passed to the sensor by the wave guide. The performance of the thermometer will therefore depend in great measure on the design of the wave guide and its relationship with the other components of the thermometer.
Another important consideration in system design is the durability of the precisely arranged components. A system that leaves the factory with acutely sensitive settings that are quickly lost within the first few days of use has significantly reduced value to the consumer. Indeed, thermometers that become inaccurate through the normal bumping and shaking encountered in daily use are of limited value regardless of the initial accuracy from the factory. It has, therefore, become a critical aspect of thermometer design to devise an arrangement of operative elements that incorporates a ruggedness and durability sufficient to withstand daily abuse in practice without significant loss of performance.
To attain these objectives, much progress has been made in packaging the electronics and electro-mechanical components to withstand typical daily rigors of use. These are important advancements that allow greater use of the product at less cost and concern about abuse. Notwithstanding this progress, IR thermometers remain prone to loss of fidelity due to normal bumps. This fidelity loss is often traced to the optics discussed above, wherein heavy handed use causes slight but signal disruptive misalignment of the wave guide. Significant misalignment of the optics will dramatically curtail the IR thermometers accuracy.
It was with this understanding of the problems associated with prior optic system design that led to the present invention.